Numbers having three 1's in base 10.

Terms

a(0) =111a(1) =1011a(2) =1101a(3) =1110a(4) =1112a(5) =1113a(6) =1114a(7) =1115a(8) =1116a(9) =1117a(10) =1118a(11) =1119a(12) =1121a(13) =1131a(14) =1141a(15) =1151a(16) =1161a(17) =1171a(18) =1181a(19) =1191a(20) =1211a(21) =1311a(22) =1411a(23) =1511a(24) =1611a(25) =1711a(26) =1811a(27) =1911a(28) =2111a(29) =3111